linux-stable.git/fs/splice.c, branch linux-2.6.28.y

splice: fix deadlock in splicing to file

2009-05-02T17:56:47+00:00

upstream commit: 7bfac9ecf0585962fe13584f5cf526d8c8e76f17

There's a possible deadlock in generic_file_splice_write(),
splice_from_pipe() and ocfs2_file_splice_write():

 - task A calls generic_file_splice_write()
 - this calls inode_double_lock(), which locks i_mutex on both
   pipe->inode and target inode
 - ordering depends on inode pointers, can happen that pipe->inode is
   locked first
 - __splice_from_pipe() needs more data, calls pipe_wait()
 - this releases lock on pipe->inode, goes to interruptible sleep
 - task B calls generic_file_splice_write(), similarly to the first
 - this locks pipe->inode, then tries to lock inode, but that is
   already held by task A
 - task A is interrupted, it tries to lock pipe->inode, but fails, as
   it is already held by task B
 - ABBA deadlock

Fix this by explicitly ordering locks: the outer lock must be on
target inode and the inner lock (which is later unlocked and relocked)
must be on pipe->inode.  This is OK, pipe inodes and target inodes
form two nonoverlapping sets, generic_file_splice_write() and friends
are not called with a target which is a pipe.

Signed-off-by: Miklos Szeredi 
Acked-by: Mark Fasheh 
Acked-by: Jens Axboe 
Signed-off-by: Linus Torvalds 
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

System call wrappers part 31

2009-01-18T18:44:01+00:00

commit 836f92adf121f806e9beb5b6b88bd5c9c4ea3f24 upstream.

Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

fs: remove prepare_write/commit_write

2008-10-30T18:38:45+00:00

Nothing uses prepare_write or commit_write. Remove them from the tree
completely.

[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Don't allow splice() to files opened with O_APPEND

2008-10-09T21:26:38+00:00

This is debatable, but while we're debating it, let's disallow the
combination of splice and an O_APPEND destination.

It's not entirely clear what the semantics of O_APPEND should be, and
POSIX apparently expects pwrite() to ignore O_APPEND, for example.  So
we could make up any semantics we want, including the old ones.

But Miklos convinced me that we should at least give it some thought,
and that accepting writes at arbitrary offsets is wrong at least for
IS_APPEND() files (which always have O_APPEND set, even if the reverse
isn't true: you can obviously have O_APPEND set on a regular file).

So disallow O_APPEND entirely for now.  I doubt anybody cares, and this
way we have one less gray area to worry about.

Reported-and-argued-for-by: Miklos Szeredi 
Acked-by: Jens Axboe 
Signed-off-by: Linus Torvalds

mm: rename page trylock

2008-08-05T04:31:34+00:00

Converting page lock to new locking bitops requires a change of page flag
operation naming, so we might as well convert it to something nicer
(!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked).

This also facilitates lockdeping of page lock.

Signed-off-by: Nick Piggin 
Acked-by: KOSAKI Motohiro 
Acked-by: Peter Zijlstra 
Acked-by: Andrew Morton 
Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Linus Torvalds

[patch 3/5] vfs: change remove_suid() to file_remove_suid()

2008-07-27T00:53:16+00:00

All calls to remove_suid() are made with a file pointer, because
(similarly to file_update_time) it is called when the file is written.

Clean up callers by passing in a file instead of a dentry.

Signed-off-by: Miklos Szeredi

splice: use get_user_pages_fast

2008-07-26T19:00:06+00:00

Use get_user_pages_fast in splice.  This reverts some mmap_sem batching
there, however the biggest problem with mmap_sem tends to be hold times
blocking out other threads rather than cacheline bouncing.  Further: on
architectures that implement get_user_pages_fast without locks, mmap_sem
can be avoided completely anyway.

Signed-off-by: Nick Piggin 
Cc: Dave Kleikamp 
Cc: Andy Whitcroft 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Andi Kleen 
Cc: Dave Kleikamp 
Cc: Badari Pulavarty 
Cc: Zach Brown 
Cc: Jens Axboe 
Reviewed-by: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

splice: fix generic_file_splice_read() race with page invalidation

2008-07-04T07:52:14+00:00

If a page was invalidated during splicing from file to a pipe, then
generic_file_splice_read() could return a short or zero count.

This manifested itself in rare I/O errors seen on nfs exported fuse
filesystems.  This is because nfsd uses splice_direct_to_actor() to read
files, and fuse uses invalidate_inode_pages2() to invalidate stale data on
open.

Fix by redoing the page find/create if it was found to be truncated
(invalidated).

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

splice: handle try_to_release_page() failure

2008-05-28T12:49:27+00:00

splice currently assumes that try_to_release_page() always suceeds,
but it can return failure. If it does, we cannot steal the page.

Acked-by: Mingming Cao

splice: fix sendfile() issue with relay

2008-05-28T12:49:27+00:00

Splice isn't always incrementing the ppos correctly, which broke
relay splice.

Signed-off-by: Tom Zanussi 
Tested-by: Dan Williams 
Signed-off-by: Jens Axboe